An Internally Transparent Collector-Insulated Gate Bipolar Transistor (abbreviated as ITC-IGBT) is evolved from a conventional punch-through IGBT. As shown in FIG. 1, a high recombination layer 2 with defect centers and recombination centers in high concentration is introduced around a collector junction in a collector region 1, and the carriers in the high recombination layer 2 have sharply reduced lifetime, thus the collector region 1 at the rear side has a reduced injection efficiency, thereby causing a low concentration of carriers in a drift region 3. When the IGBT is turned off, the carriers in the drift region 3 are extracted by an electric field quickly, thereby improving the operating frequency of the IGBT.
In the conventional technology, generally Helium ion implantation or proton radiation is used to obtain a high recombination layer. However, by means of the Helium ion implantation or proton radiation, atoms (or ions) can not be implanted to a sufficient depth, and the obtained high recombination layer is thin.
In order to solve the above problems, it is proposed that a silicon-silicon bonding technology is used to obtain a high recombination layer. That is, impurities for the high recombination layer are implanted into an substrate, and Helium ions are implanted into the substrate to form the high recombination layer, then the high recombination layer bonds with another substrate, finally a front structure and a rear structure of the IGBT are formed by means of a process of fabricating the punch-through IGBT, and thus the ITC-IGBT is prepared. However, the process is complex.